Exploring demographic differences and outcomes in young-onset colorectal cancer.

Abstract

35 Background: Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States (1). The incidence of young-onset CRC is on the rise based on recent data (2). Previous research on other cancers has shown that patients living in rural areas have worse outcomes (3). This study aimed to investigate the geographic and socio-demographic disparities in young-onset CRC patients. Methods: We conducted a retrospective study on colorectal cancer patients between 1975 and 2016 using the Surveillance, Epidemiology, and End Results (SEER) database. Both univariate and multivariable analyses were performed to evaluate overall survival (OS) and disease-specific survival (DSS). Socio-demographic factors, including the location of residence [metro area (MA) or rural area (RA)], gender, race, insurance status, and marital status, were analyzed. Young-onset colorectal cancer (CRC) was defined as the age of diagnosis less than 50 years. The program used for analysis was SAS software 9.4 (SAS Institute Inc., Cary, NC, USA.) Univariate and multivariable models were analyzed using Cox proportional models. Demographic differences between urban and rural population were assessed using Wilcoxon Rank Sum test (continuous variable) and Chi-square test (categorical variables). Results: A total of 73,378 [RA, N = 7,636(10.6%); MA, N = 64,605(89.4%)] young-onset CRC patients were included. RA had more Caucasian patients compared to MA (80.5% vs 60%, p < 0.001). Patients living in RA were more likely to be uninsured (4.8% vs 3%, p < 0.001) than MA. During the study period, the incidence and mortality rates were consistently higher in RA vs. MA. Univariate and multivariable analysis showed that RA had worse OS (multivariate HR = 1.14; p < 0.01) and DSS (multivariate HR = 1.15; p < 0.001) compared to MA. Similarly, males, single and uninsured patients had worse OS and DSS compared to females, married, and insured patients, respectively. Conclusions: Our study identified social and demographic disparities in young-onset CRC incidence and outcomes. Potential causes may include access to healthcare, diet, health behavior, and environmental factors. Future research is needed to understand and attenuate such disparities.